The GNO Orchestra was founded in 1939 together with the opera company, then a department of the Royal Theatre. It covers the breadth of the lyrical repertory, from Monteverdi to contemporary composers. It also performs symphonic music concerts. It has been directed by acclaimed conductors, among which: O. Dimitriades, A. Evangelatos, T. Karalivanos, M. Karydis, A. Paridis, D. Chorafas, A. Gatto, F. Capuana, N. Resicgno and T. Serafin. It has also worked with famous Greek and foreign singers: I. Angelopoulos, Z. Vlachopoulou, P. Epitropaki, N. Zachariou, D. Theodosiou, D. Kavrakos, M. Callas, M. Krilovici, O. Lappa, N. Moschona, T. Xirelli, K. Paschali, M. Perra, Z. Pylou, A. Sgourda, T. Vickers, N. Ghiuselev, T. Gobbi, M. Guleghina, N. Martinucci, C. Bergonzi, P. Burchuladze, L. Nucci, G. Dimitrova, R. Panerai, L. Rysanek, R. Scotto, G. Taddei, G. Giacomini, and more.
The orchestra appears regularly at the Athens Festival and at the Athens Concert Hall. Today it is conducted by Lucas Karytinos and Ilias Voudouris (chief). In 2000, the Friends of the Greek National Opera society awarded it the Apollo Prize.